A particularly advantageous application of the invention lies in the field of techniques for connecting optical fibers, both multimode and monomode.
The use of connection endpieces is becoming more and more commonplace in connectors for optical fibers. This type of device considerably simplifies the problem of assembling and positioning the fiber in the connection member. Also, although the cost of endpieces remains relatively high, they now provide full satisfaction to users and it is to be expected that the use thereof will continue to grow in the future.
At present, nearly all optical fiber connection endpieces are made of ceramics, and in particular of zirconia. Nevertheless, French patent application No. 90 01 300 (not yet published), teaches a method of making connection endpieces out of silica by fiber-drawing, which method is suitable for directly obtaining very high geometrical accuracy (inside diameter, outside diameter, concentricity), at low cost, with excellent mechanical strength and with surface states that are considerably better than those obtained by extruding and machining ceramic endpieces.
However, making the inlet cone of the endpiece for facilitating insertion of the optical fiber into the capillary requires machining that is slow, very difficult, and expensive, and which requires strict and expensive quality control.
Thus the technical problem to be solved by the present invention is to provide a method of making an inlet cone at one of the ends of a connection endpiece for optical fibers, said endpiece being in the form of a cylindrical rod of outside diameter D, and including an internal capillary of diameter d.sub.i, the method making it possible to make said inlet cone at low cost while still satisfying the accuracy requirements of optical fiber connection technology.